The Zika Virus is the latest mosquito vectored virus to explode across the Western Hemisphere, following increases Dengue, the 2013 introduction of Chikungunya into the Caribbean and now Zika. Zika virus was first documented in Uganda almost 60 years ago. Few cases were reported and the virus was mostly confined to Africa. In 2015, Brazil reported 1.5 million cases of Zika. The introduction may be related to the large number of international travelers to the World Cup in 2014.
Four in five people infected are asymptomatic. For the other 20%, the symptoms are mild: headache, rash, mild fever, bone and joint pain. Symptoms typically dissipate in less than a week. An estimated one in four people infected with the virus are asymptomatic. Infected people should be isolated from mosquitoes for one week to prevent spread of the virus. Virus remains in the bloodstream and is available for transmission to a mosquito population. It is more difficult to stop the spread of this virus by quarantine because so many are asymptomatic.
In Brazil, the 1.5 million cases of Zika virus correlate with a rise in other diseases, a disturbing development. Guillain-Barre syndrome is an autoimmune disease that attacks and damages the nervous system. It typically follows a fever. Some Brazilians with Zika have also developed Guillain-Barre syndrome. The proposed mechanisms: A virus invades myelin cells and other cells of the nervous system. The external cell proteins are altered, recognized as foreign and attacked by the immune system. The link to Zika is under study.
The Zika epidemic in Brail is correlated to the rise of microcephaly in which the heads of babies do not develop to full size and are abnormally small. In 2015, 3500 cases of microcephaly were reported in Brazil which is 20 times normal. Mothers of these babies also reported Zika virus. It is possible that a Zika infection in pregnant mothers can lead to microcephaly. The CDC has issued a travel alert for pregnant women to avoid travel to foreign countries experiencing Zika outbreaks, roughly most of the Caribbean and the countries from Brazil in the south to Mexico in the north.
The Asian Tiger mosquito (Aedes albopictus) can vector Zika along with other viruses. The Asian Tiger mosquito is an invasive species now permanently established in the US. There is potential for spread of Zika in the United States during warm months when mosquitos are active. Florida, Texas and Hawaii are most at risk. Efforts at mosquito control become increasingly important as new exotic mosquito transmitted diseases are introduced to new areas.